This invention relates to captive panel screw assemblies and in particular to a new and improved captive panel screw washer construction.
Edge lighted panel assemblies are widely used in aircraft cockpits. A typical edge lighted panel assembly includes a front panel made of a clear plastic carrying legends identifying components and functions. This plastic panel is illuminated by miniature lamps positioned at the edges and/or at locations within the panel. Some times the panel is backed with a thin printed circuit to which the lamps are attached. The lighted panel is attached to a metal plate on which switches and other control devices are mounted, with switches and controls projecting through openings in the panel.
The panel is removed from the plate from time to time for inspection and maintenance of the lights, switches and other controls. Screws are used to attach the panel to the support plate and it is desirable to have the screw and associated hardware carried in the panel in some manner so the screws do not become separated and lost during such maintenance operations.
Captive screws and washers have been used in the past, and one such combination is shown in U.S. Pat. No. 3,218,906. It is an object of the present invention to provide a new and improved screw and washer configuration which can be made captive to an edge lighted panel or the like, while permitting ease of attachment and removal of the panel.
A further object is to provide such a fastener configuration which does not require special tools to install nor special tools to use and which minimizes the possibility of damage to the panel on installation and removal. An additional object is to provide such a fastener arrangement which will provide a tight assembly while tolerating a wide mismatch in hole alignment, and one which will provide a cushioned grip which tends to resist loosening resulting from vibration.
These and other objects, advantages, features and results will more fully appear in the course of the following description.